1. Field of the Invention
The field of the present invention relates generally to keyboards, more particularly to keyboards possessing fewer keys than the number of characters which may be generated by using the keyboard, and most specifically to such keyboards which utilize linked keystrokes to generate characters.
2. General Background
In the present time, often known as the xe2x80x98information agexe2x80x99 information is transmitted by use of both analog and digital means. The pager and cellular phone are two examples of portable communication tools which receive, and transmit as well as receive, respectively, radio signals which may be analog in the case of the cellular phone are strictly digital in the case of the pager though the cellular phone may permit support digital communication as well. More recent and sophisticated portable communication tools associated with xe2x80x98personal communication systemsxe2x80x99 (PCS) enable radio facsimile transmission/reception and internet access. Various capabilities are also offered on portable telephones, cellular or otherwise, which are based upon internal memory and the software held in microprocessors. Such capabilities include automatic dialing of telephone numbers and display of the number and name of a current caller.
All these portable communication tools utilizing radio transmission and reception are considered to be characterized by the use of a numeric keypad possessing the digits 0 through 9 and at least two other keys, xe2x80x98*xe2x80x99 and xe2x80x98#xe2x80x99. This is based upon a standard telephone keypad which is required for entering a telephone number. Additional dedicated function keys facilitate memory input of such numbers for automatic dialing and may also have dual functions as determined by another dedicated key. A key is typically dedicated to switching the power supply as well.
The input of alphabetic characters, i.e. letters, into memory is also known upon such devices wherein a shifting of mode is first effected by striking either the xe2x80x98*xe2x80x99 or xe2x80x98#xe2x80x99 key followed by either one, two or three strokes of the same key to obtain xe2x80x98Axe2x80x99, xe2x80x98Bxe2x80x99, or xe2x80x98Cxe2x80x99 for example with the key labeled xe2x80x981xe2x80x99. And telephones with memory are known which allow the creation of names by selecting from a sequential tour of the alphabet for each letter desired. If the letter xe2x80x98nxe2x80x99 is desired, for instance, the letters a-m are first waived or z-o is backed through and the xe2x80x98nxe2x80x99 selected. For each letter selected the preceding or succeeding letters of the alphabet must be considered by the device. While many of these devices may have up to twenty different keys the inclusion of the entire alphabet with a key dedicated to each letter of the same is not considered feasible. The basic twelve key numeric keypad mentioned above is necessary and additional function keys are also required. The addition of the twenty-six keys required of the English alphabet to the sixteen or more keys already necessary is believed to be excessively consumptive of space for a hand held device. One cannot use both hands to type on a device which is held in one hand in any case.
Secondly, it is noted that the standard keyboard utilized in association with computers which typically possesses over one hundred keys utilizes a number of function keys each of which, stroked while another type of function key, such as the xe2x80x98Shiftxe2x80x99 or xe2x80x98Altxe2x80x99 or xe2x80x98Crtlxe2x80x99 key is held down, provides several different functions. The xe2x80x98Shiftxe2x80x99 key, of course, was first utilized in this manner with manual typewriters to obtain upper case letters and ten other characters: xe2x80x98!xe2x80x99, xe2x80x98@xe2x80x99, xe2x80x98#xe2x80x99, xe2x80x98$xe2x80x99, xe2x80x98%xe2x80x99, xe2x80x98{circumflex over ( )}xe2x80x99, xe2x80x98andxe2x80x99, xe2x80x98*xe2x80x99, xe2x80x98(xe2x80x98,xe2x80x99)xe2x80x99; and is still utilized in this manner on the standard one hundred and four key keyboard presently being used to write this document as upper cases for the numbers 1-0 respectively.
It is emphasized that this multiple use of keys requires holding a dedicated function key while another key is stroked. This effectively means that this system cannot be practically utilized upon a hand held device, which is also known herein as a xe2x80x98palmtopxe2x80x99 computer and is inclusive of the communication devices discussed above as well as numerical calculators and other devices using a microprocessor and a keypad for input.
Thirdly, it is considered that many people do not possess full use of both hands and for these people operation of a keyboard requiring simultaneous keystrokes to generate a given character or function is not feasible. Furthermore, standard keyboards with over eighty keys invariably have the keys in close proximity to each other and many people with various physical and neurological disabilities cannot operate these keyboards for this reason.
Fourthly, it is considered well known that the standard QWERTY keyboard requires thorough memorization before one can begin to operate the same with any efficiency, that a great deal of practice is normally required to obtain genuine efficiency after memorization, and that, no matter how practiced an operator of a QWERTY keyboard may be, the fixed configuration of the keys is not well suited to the frequency of the letters typed and the movement of the fingers required. The key dedicated to xe2x80x98Jxe2x80x99, for instance is located directly under the index finger of the right hand in correct QWERTY keyboard operation. This key, and the key dedicated to the letter xe2x80x98Kxe2x80x99 immediately to the right of the xe2x80x98Jxe2x80x99 are the easiest keys for a right handed person to stroke repetitively; but neither key has frequent usage. In fact, the Italian alphabet, based upon the same Roman alphabet from which the twenty-six letter English alphabet is derived, lacks both these letters altogether for the entire language and the only use of these two letters is for adopted foreign words. In other words, the xe2x80x98Jxe2x80x99 and xe2x80x98Kxe2x80x99 keys are rarely touched by any writer of Italian. This is not to say that QWERTY keyboards are of no use in Italy but that the fixed configuration of keys in the QWERTY layout is considered generally unfortunate with regard to ergonomics in addition to difficulty in memorizing and mastering.
Statement of Need
The above discussion of xe2x80x98palmtopxe2x80x99 computers, which are hand held communication tools possessing both a microprocessor and a keypad or keyboard for input, regardless of other features and capabilities such as radio reception/transmission, firstly indicates that it is considered desirable to have the ability to efficiently input alphabetic characters, i.e. letters, into a device which is too small to permit use of a keyboard possessing individual keys each dedicated to one letter.
Secondly, it is noted that the manner in which multiple characters or functions from a single key is derived with a standard typewriter or computer keyboard, i.e. simultaneous stroking of two different keys, one of which is a dedicated function key, is not feasible upon a hand held device and also that many people lack the use of both hands and cannot effectively operate a keyboard requiring simultaneous keystrokes.
It is thirdly considered that many people, particularly those having a physical or neurological disability which is manifested by poor motor coordination, cannot use a standard QWERTY keyboard either. The spacing between the keys is too close and the number of keys too many to allow use by many people lacking the motor coordination required to effect accurate keystrokes on such a keyboard.
It is fourthly considered that the standard QWERTY keyboard: is difficult to learn; requires considerable practice to master and; is known to possess less than an optimum configuration with regard to frequency of key strokes and the movement of the fingers required in operation.
It is hence considered, for all these reasons, that a poignant need therefore exists for a keyboard which:
(a) is capable of efficiently generating alphabetic characters, i.e. letters, with a fixed configuration of keys which number less than the number of letters in an alphabet;
(b) does not require the simultaneous depression of multiple keys, i.e. simultaneous keystrokes;
(c) can be effectively operated by people who cannot operate a standard keyboard because of the number and proximity of keys upon the same;
(d) does not require the type of memorization necessary to efficiently operate a standard QWERTY keyboard.
Objects of the Invention
A first principal object of the present invention is the provision for efficient generation of all the characters of an alphabet with operation of a keyboard possessing a lesser number of keys than the number of letters in the alphabet.
A second principal object of the present invention is the provision of a keyboard which does not require simultaneous keystrokes so that the keyboard is both suitable to a hand held device and to an otherwise supported keyboard which may be effectively operated by people lacking the full use of both hands.
A third principal object of the present invention is provision of a keyboard which can be effectively utilized to generate all the characters of an alphabet with operation by a person who is unable to operate a standard keyboard because of the number and proximity of the keys in fixed configuration thereon.
A fourth principal object of the present invention is the provision of a keyboard which can be learned intuitively and which does not require memorization.
Auxiliary objects of the present invention include provision of a keyboard which is ergonomic with regard to key configuration, which does not require extensive practice to master, and which is generally easy to use.
Principles Relating to the Present Invention
All of the objects described above are enabled with appropriate software contained in a communications tool which observes the principles relating to the present invention wherein linkage between sequential pairs of keystrokes generating a given character is established by one of three methods. One method is simply to provide a delimiting key which, stroked after stroking two other keys in sequence, indicates that said two keys are linked and the character associated with that sequentially linked pair of key strokes is desired. This method enables single keystrokes to be recognized as pertaining to another particular character as well but this still requires two keystrokes including stroking of the delimiting key and this method requires three keystrokes at a minimum for the generation of characters associated with linked pairs of keystrokes.
The second method of establishing sequential pairs of keystrokes for generating a given character involves utilization of an interval threshold for the time elapsed between keystrokes. If the time elapsed between any two keystrokes in sequence is less than the threshold interval the two keystrokes are recognized as indicating the generation of a given character. If the time elapsed between any two keystrokes in sequence is more than the threshold interval the first keystroke is recognized as indicating the generation of another given character. Only one or two keystrokes, followed by a slight pause, is required for the generation of a given character following this method. In utilization of this method it is further desirable to provide the capability of setting and changing the length of time employed as the interval threshold.
The third method of establishing sequential pairs of keystrokes for generating a given character also involves utilization of an interval threshold for the time elapsed between keystrokes but the interval threshold is established in response to the typing speed of the operator with utilization of an adaptive predictive algorithm which adjusts the interval threshold utilized to reflect varying typing speeds. The adaptive predictive algorithm essentially begins with a given baseline value for the interval threshold and utilizes a running average, essentially, of keystroke frequency in modifying the interval threshold utilized.
It is suggested that the characters generated by linked pairs of keystrokes be represented upon the keyboard between the two keys and that location of the character represented immediately adjacent one of these two keys indicate that this key is the first of the sequential pair of keys to be stroked in order to generate that character. It is observed that if a rectilinear configuration of keys is utilized possessing rows and columns each key in the configuration possesses the ability to be linked with at least three other vertically, horizontally, or diagonally, adjacent keys and that interiorly located keys may readily possess linkage with eight other keys. Given the ability to use each key independently as well as in a linked pair of keystrokes for the generation of a unique character a simple twelve key keypad of the type found on ordinary telephones yields eighty different characters or functions which is considered sufficient to provide the basic capabilities of either a xe2x80x98palmtopxe2x80x99, i.e. hand held, or xe2x80x98notebookxe2x80x99 computer.
The difference between the two is considered to be mainly one of size as well as capabilities. The xe2x80x98notebookxe2x80x99 computer has a display screen though it may or may not be held in a hand and the xe2x80x98palmtopxe2x80x99 computer might lack a display screen. A xe2x80x98laptopxe2x80x99 computer is not held in a hand and has a display screen large enough to make effective use of full word processing functions while the xe2x80x98notebookxe2x80x99 computer may have a screen and some functions sufficient for basic editing.
If only six keys are utilized in a hexagonal pattern a total of twenty-seven characters are readily obtained with single (6) and repeated (6) keystrokes of the same key combined with (5+4+3+2+1) bi-directional sequentially linked keystrokes in which the order of the two different keys stroked is immaterial. This is sufficient for generation of all the letters of the English alphabet. If unidirectional sequentially linked keystrokes are utilized in which the order in which two different keys are stroked is determinative of the character generated 42 unique characters are available: (6)+(6)+6(5)=42. This configuration is suggested particularly for a communication device enabling people who cannot operate a standard QWERTY keyboard by reason of the number and proximity of the keys as the six keys in a hexagonal pattern may be spaced generously apart from one another.
It is also considered important to fulfillment of the principles relating to the present invention that simultaneous keystrokes be avoided, otherwise operation upon a hand held device is impractical and a keyboard which is otherwise supported may be operated by people who lack the full use of both hands. It is further considered in this regard that more than two sequential keystrokes may be linked in fulfillment of said principles and that a linked sequence of keystrokes may involve only one key. Stroking the same key twice or thrice in quick succession wherein the interval between successive keystrokes is less than the threshold interval followed by an interval exceeding the threshold interval might generate two other characters besides a first character obtained by stroking the key once.
It is preferred, however, that only pairs of linked keystrokes be utilized in order to achieve efficiency. Efficiency is defined, for the purposes of the present invention, as the number of keystrokes required to generate a given character. One, by this definition, represents maximum efficiency and is obtained only by use of keys dedicated to a single character which, for the purposes of the present invention, is not a feasible option. The use of only linked pairs of sequential keystrokes and single keystrokes, both recognized with use of a threshold interval, yields an efficiency of less than two. The use of more than two linked keystrokes would obviously be less efficient and for this reason is not recommended.
Lastly, the capabilities associated with a standard computer keyboard of over eighty keys including the standard QWERTY keyboard with the ten 1-0 numeric keys and secondary upper case symbols, the shift key, control key, alternate key, four cursor keys, the enter key, page up and down keys, insert, home, delete, escape, tab, Caps Lock, back space key, and the multiple function keys typically found on such a keyboard, are considered. Using only single and linked pair keystrokes in accordance with the principles relating to the present invention it is found that only sixteen keys are required to yield all the above characters and functions just mentioned. Over ninety distinct characters and functions are readily generated with such a keyboard and the essential capabilities of a full size keyboard thus made available with a keyboard which may be placed on a hand held device or have the keys spaced apart sufficiently upon an otherwise supported keyboard to enable people who cannot operate a standard keyboard because of the number and proximity of the keys to each other to achieve the capabilities of a standard keyboard.